Optical film having multi-story and multi-peak prisms

ABSTRACT

An optical film comprises: a transparent supporting layer, and a plurality of multi-story prisms having multiple peaks formed thereon and juxtapositionally integrally formed on the supporting layer, each peak of the prism tapered or narrowed upwardly towards a light output direction for increasing a light concentrating effect of the prism in order to increase the brightness of the optical film.

BACKGROUND OF THE INVENTION

This application is an improvement of the prior application also filedby the same inventor of this application.

The prior application was filed on Mar. 3, 2006 given with anapplication Ser. No. 11/366,870, of which a typical drawing figure isattached herewith (as shown in FIG. 1) of this application.

The optical film of the prior application as shown in FIG. 1 includes aplurality of prisms 6 juxtapositionally formed on a supporting layer 5.

Each prism 6 of the prior application includes: a lower prism element 61integrally formed with the supporting layer 5 and having two lowerdihedral faces 6 a, 6 b disposed on opposite sides of the lower prismelement 61 and cooperatively defining a first apex angle θ₁ between thetwo lower dihedral faces 6 a, 6 b; and an upper prism element 62integrally superimposed on the lower prism element 61 and having twoupper dihedral faces 7 a, 7 b disposed on opposite sides of the upperprism element 62 and cooperatively defining a second apex angle θ₂between the two upper dihedral faces 7 a, 7 b; with the two lowerdihedral faces 6 a, 6 b forming a first apex E₁, which is positionedbelow a second apex (E₂) as formed by the two upper dihedral faces 7 a,7 b.

However, such a prior art has its first apex E₁ superimposed and“concealed” under the second apex E₂, thereby limiting a lightconcentrating effect of the prism 6, and influencing the luminance,brightness and luminous flux of an optical film thus formed.

The present inventor has made an improvement based upon the prior art byforming multi-peak and multi-story prisms on the supporting layer of theoptical film.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an optical filmcomprising: a transparent supporting layer, and a plurality ofmulti-story prisms having multiple peaks formed thereon andjuxtapositionally integrally formed on the supporting layer, each peakof the prism tapered or narrowed upwardly towards a light outputdirection for increasing a light concentrating effect of the prism inorder to increase the brightness of the optical film.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an optical film of the prior art.

FIG. 2 shows a first preferred embodiment of the present invention.

FIG. 3 is a modification of the embodiment as shown in FIG. 2.

FIG. 4 shows another preferred embodiment of the present invention.

FIG. 5 shows another modification based on the embodiment as shown inFIG. 2.

FIG. 6 shows further preferred embodiment of the present invention.

FIG. 7 shows a modification based on the embodiment as shown in FIG. 6.

DETAILED DESCRIPTION

As shown in FIG. 2, the optical film of the present invention comprises:a transparent supporting layer 1, a basic prism 2 integrally formed onthe supporting layer 1, and at least a parasitic prism 3 integrallyformed on the basic prism 2.

The basic prism 2 is formed by two basic dihedral faces 21, 22 taperedupwardly towards a light output direction towards a viewer as generallyindicated by numeral “L” as shown in FIG. 2 to define a first apex angleθ₁ between the two dihedral faces 21, 22, which may be 104° or any otherproper degrees, having the two basic dihedral faces 21, 22 convergentlyintersected to form a first apex (or first peak) 23 on the top of thebasic prism 2.

The parasitic prism 3 is formed by two parasitic dihedral faces 31, 32tapered upwardly to define a second apex angle θ₂, which may be a rightangle or an acute angle, having the two parasitic dihedral faces 31, 32convergently intersected to form a second apex (or second peak) 33 onthe top of the parasitic prism 3.

The second apex 33 is higher than the first apex 23 (H₂>H₁) so that theparasitic prism 3 may absorb the incidence light projecting into theparasitic prism 3 to reduce light loss of the optical film. Meanwhile,the prism 3 is tapered or narrowed upwardly to enhance its lightconcentrating effect. The basic prism 2 and the parasitic prism 3 havetwo peaks 23, 33 to thereby increase the brightness, luminance andluminous flux of the optical film, to be superior to the prior art.

The prisms 2, 3 may form two storys and there are two peaks (or twoapexes). Accordingly, the present invention may be designated as anoptical film having multi-story & multi-peak prisms.

The transparent supporting layer 1 may be made of thermoplastic resinincluding polyethylene terephthalate (PET), polycarbonate (PC), etc.

The prisms 2, 3 may be made of photo-sensitive or photo-curable resin orthermosetting resin including UV-curable resin, which are formed on thesupporting layer 1 by molding or printing process.

As shown in FIG. 3, one face of the two dihedral faces 21, 22 has beenformed as a curved surface 22 a. The curvature radius may be made aslarge as possible.

Each of the dihedral faces of the prism may be formed as a flat orcurved face, not limited in this invention.

The second apex 33 is formed on a left side of the first apex 23.However, the second apex 33 may also be positioned at the right side ofthe first apex 23.

The face 21 of the dihedral faces 21, 22 as shown in FIG. 2 may also beformed as a curved surface (not shown). Or, both dihedral faces 21, 22may be formed as curved faces respectively.

As shown in FIG. 4, the optical film includes: a basic prism 2integrally formed on the supporting layer 1 having a first apex 23formed on a top of the basic prism 2 as convergently intersected by twobasic dihedral faces 21, 22 tapered upwardly for defining a first apexangle θ₁; a first parasitic prism 3 integrally formed on the basic prism2 having a second apex 33 formed on a top of the first parasitic prism 3as convergently intersected by two parasitic dihedral faces 31, 32tapered upwardly for defining a second apex angle θ₂; and a secondparasitic prism 4 integrally formed on the basic prism 2 andjuxtapositated opposite to the first parasitic prism 3, having a thirdapex 43 formed on a top of the second parasitic prism 4 as convergentlyintersected by two parasitic dihedral faces 41, 42 tapered upwardly fordefining a third apex angle θ₃.

The third apex 43 may be higher than the second apex 33. Of course, theangle of each apex angle and the height of each apex is not limited inthe present invention.

Preferably, at least one peak of the prisms should be the tallest amongthe peaks of the prisms in order to efficiently “catch” any incidencelight projected inwardly from any external light sources or directionsto prevent light loss of the optical film.

The first apex 23 of the basic prism 2 is “sandwiched” in between thetwo apexes 33, 43 of the two parasitic prisms 3, 4.

As shown in FIG. 4, the first apex 23 is coincidently located at the“valley” in between the two prisms 3, 4. However, the first apex 23 mayalso be protruded upwardly (not shown) to form triple peaks or apexes ona top portion of the basic prism 2 for increasing light concentratingeffect of the optical film.

As shown in FIG. 5, the first apex 23 of the basic prism 2 asaforementioned has been modified to be a round peak or apex 23 a, whichbecomes a preferred embodiment of the present invention.

As shown in FIG. 6, the parasitic prism 3 has its dihedral faces 31, 32tapered upwardly respectively from the first apex 23 of the basic prism2 and a right face 22 of the dihedral faces 21, 22 of the basic prism 2.The parasitic prism 3 is tapered upwardly to be narrower than the prismelement (62) of the prior art as dotted line shown in FIG. 6 to increaseits light concentrating effect of the optical film.

As shown in FIG. 7, the left face 21 of the dihedral faces 21, 22 of thebasic prism 2 as shown in FIG. 6 has now been modified to be a curvedface 21 a and the right face 22 of the basic prism 2 has now been formedas a “base” of the parasitic prism 3 and been encompassed by the twodihedral faces 31, 32 of the parasitic prism 3. This is a furthermodification based on the embodiment as shown in FIG. 6.

The angles, shapes, heights, number of the prisms and peaks (or apexes)are not limited in the present invention. The number of storys of theprisms are also not limited.

The multiple or plural parasitic prisms may be juxtapositionally formedon the basic prism 2, or partially superimposed on the basic prism 2 topresent multiple or plural peaks or apexes of the parasitic prismsformed on an upper or top portion of the basic prism 2 to increase thelight concentrating effect of the optical film.

The present invention also comprises a method by forming, molding orprinting the structured layer or layers including the multiple parasiticprisms and multiple peaks of the parasitic prisms on the basic prism.

The present invention may be modified without departing from the spiritand scope of the present invention.

I claims:
 1. An optical film comprising: a transparent supporting layer;a basic prism integrally formed on said supporting layer and having twobasic dihedral faces of said basic prism tapered upwardly from saidsupporting layer to define a first apex angle between the two basicdihedral faces and to form a first apex or peak on a top of said basicprism as convergently intersected by the two basic dihedral faces; andat least a parasitic prism integrally formed on said basic prism andhaving two parasitic dihedral faces of said parasitic prism taperedupwardly from one face of said two basic dihedral faces of said basicprism to define a second apex angle between said two parasitic dihedralfaces and to form a second apex or peak on a top of said parasitic prismto be juxtapositioned to said first apex of said basic prism for formingmultiple peaks above an upper or top portion of said basic prism forincreasing a light concentrating effect.
 2. An optical film according toclaim 1, wherein each said peak of said prism is formed as a round peak.3. An optical film according to claim 1, wherein each said face of saiddihedral faces of the prism is selected from a flat face and a curvedface.
 4. An optical film according to claim 1, wherein said prismsinclude at least a peak which is the tallest among the multiple peaks ofsaid prisms.
 5. An optical film according to claim 1, wherein one saidparasitic prism includes said two parasitic dihedral faces taperedupwardly respectively from said apex of said basic prism and from oneface of said two basic dihedral faces of said basic prism.
 6. An opticalfilm according to claim 1, wherein said parasitic prism is tapered andnarrowed upwardly towards a light output direction.
 7. A process formaking the optical film as set forth in claim 1 by integrally forming,molding or printing at least one said parasitic prism on said basicprism integrally formed on said supporting layer.